var i: integer;
...
Randomize;
i:=Random(ListBox1.Items.Count-1);
ListBox1.ItemIndex:=i;

type
  TMatrix = array [1..n,1..m] of integer;


function FindStr(Matrix: TMatrix): boolean;
var
  counter, i, j: integer;
begin
  for i := 1 to n do
    begin
      counter := 0;

      for j := 1 to m do
        if (Matrix[i,j] mod 2 = 0) then
          inc(counter);

      if (counter = 2) then
        begin
          Result := true;
          exit;
        end;
    end;
  Result := false;
end;